19. A geometric series has first term 4 and common ratio $r$, where $0 < r < 1$.
The first, second, and fourth terms of this geometric series form three successive terms of an arithmetic series.
The sum to infinity of the geometric series is
A $\frac { 1 } { 2 } ( \sqrt { 5 } - 1 )$\\
B $2 ( 3 - \sqrt { 5 } )$\\
C $2 ( 1 + \sqrt { 5 } )$\\
D $2 ( 3 + \sqrt { 5 } )$\\